The present invention relates generally to a clutch retainer for a motor vehicle clutch assembly, and specifically to a retainer assembly that expands to maximize pressure plate travel.
Typically, a clutch is utilized to selectively transmit torque between an engine and a transmission. When the clutch is engaged, clutch levers force pressure plates against clutch disks to engage a flywheel. When the clutch is disengaged, the clutch levers are lifted from the pressure plate to disengage the pressure plates and free the clutch discs from engagement with the flywheel.
The clutch levers are moved between an engaged and disengaged position by a retainer assembly moved axially along a shaft. The retainer assembly and the clutch levers are biased toward the engaged position by a diaphragm spring. The clutch disks disengage the flywheels when a force is exerted to pull the retainer assembly toward the disengaged position. Clutch straps bias the pressure plates away from the flywheel so that when the retainer assembly is pulled toward the disengaged position the pressure plates disengage the clutch disks.
The biasing force of the diaphragm spring creates a clamp load against the flywheel. The clamp load determines the amount of torque transfer from the engine to the transmission. The engaged and disengaged positions are obtained by moving the retainer assembly along an axis to transmit a biasing force through a plurality of levers to sandwich the clutch disk between the flywheel and the pressure plate. The biasing force exerted on the pressure plates by the levers is commonly referred to as clamp load. Higher clamp loads provide better torque transfer between the engine and the transmission.
The clamp load is balanced against the amount of force required to disengage the clutch, commonly referred to as pedal effort. Typically, the clamp load is balanced against an increase in pedal effort. Further, if the pressure plates are not moved far enough away from the flywheel, the pressure plates may not completely disengage the clutch. Such a condition can cause increased wear on the friction disks. As appreciated, pulling the pressure plate further away from the flywheel require greater release assembly travel.
Accordingly, there is a need for a clutch assembly with increased clearance between the flywheel and friction disks during disengagement without a corresponding increases in release assembly travel.